You're completely right: artists who make mixes and use samples should probably do it above-board and follow all applicable copyright laws.
However, the problems are three-fold:
1) Lack of information. It looks like the new automated process provides no clues on what the infringing content was/is.
2) Lack of appeals process.
3) The fact that previously rolled out systems that have allowed major labels this sort of access to services (primarily YouTube) have been subject to abuse by the labels, taking down content that was original, and there has been no indication given that this won't happen here.
However, the problems are three-fold:
1) Lack of information. It looks like the new automated process provides no clues on what the infringing content was/is.
2) Lack of appeals process.
3) The fact that previously rolled out systems that have allowed major labels this sort of access to services (primarily YouTube) have been subject to abuse by the labels, taking down content that was original, and there has been no indication given that this won't happen here.